1 files changed, 92 insertions, 2 deletions

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 0d8b53d1b75..3d9985b17c2 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -129,6 +129,7 @@ typedef struct RI_ConstraintInfo
 	Oid			ff_eq_oprs[RI_MAX_NUMKEYS]; /* equality operators (FK = FK) */
 	Oid			period_contained_by_oper;	/* anyrange <@ anyrange */
 	Oid			agged_period_contained_by_oper; /* fkattr <@ range_agg(pkattr) */
+	Oid			period_intersect_oper;	/* anyrange * anyrange */
 	dlist_node	valid_link;		/* Link in list of valid entries */
 } RI_ConstraintInfo;
 
@@ -734,8 +735,11 @@ ri_restrict(TriggerData *trigdata, bool is_no_action)
 	 * not do anything.  However, this check should only be made in the NO
 	 * ACTION case; in RESTRICT cases we don't wish to allow another row to be
 	 * substituted.
+	 *
+	 * If the foreign key has PERIOD, we incorporate looking for replacement
+	 * rows in the main SQL query below, so we needn't do it here.
 	 */
-	if (is_no_action &&
+	if (is_no_action && !riinfo->hasperiod &&
 		ri_Check_Pk_Match(pk_rel, fk_rel, oldslot, riinfo))
 	{
 		table_close(fk_rel, RowShareLock);
@@ -753,8 +757,10 @@ ri_restrict(TriggerData *trigdata, bool is_no_action)
 	if ((qplan = ri_FetchPreparedPlan(&qkey)) == NULL)
 	{
 		StringInfoData querybuf;
+		char		pkrelname[MAX_QUOTED_REL_NAME_LEN];
 		char		fkrelname[MAX_QUOTED_REL_NAME_LEN];
 		char		attname[MAX_QUOTED_NAME_LEN];
+		char		periodattname[MAX_QUOTED_NAME_LEN];
 		char		paramname[16];
 		const char *querysep;
 		Oid			queryoids[RI_MAX_NUMKEYS];
@@ -790,6 +796,89 @@ ri_restrict(TriggerData *trigdata, bool is_no_action)
 			querysep = "AND";
 			queryoids[i] = pk_type;
 		}
+
+		/*----------
+		 * For temporal foreign keys, a reference could still be valid if the
+		 * referenced range didn't change too much.  Also if a referencing
+		 * range extends past the current PK row, we don't want to check that
+		 * part: some other PK row should fulfill it.  We only want to check
+		 * the part matching the PK record we've changed.  Therefore to find
+		 * invalid records we do this:
+		 *
+		 * SELECT 1 FROM [ONLY] <fktable> x WHERE $1 = x.fkatt1 [AND ...]
+		 * -- begin temporal
+		 * AND $n && x.fkperiod
+		 * AND NOT coalesce((x.fkperiod * $n) <@
+		 *  (SELECT range_agg(r)
+		 *   FROM (SELECT y.pkperiod r
+		 *         FROM [ONLY] <pktable> y
+		 *         WHERE $1 = y.pkatt1 [AND ...] AND $n && y.pkperiod
+		 *         FOR KEY SHARE OF y) y2), false)
+		 * -- end temporal
+		 * FOR KEY SHARE OF x
+		 *
+		 * We need the coalesce in case the first subquery returns no rows.
+		 * We need the second subquery because FOR KEY SHARE doesn't support
+		 * aggregate queries.
+		 */
+		if (riinfo->hasperiod && is_no_action)
+		{
+			Oid			pk_period_type = RIAttType(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]);
+			Oid			fk_period_type = RIAttType(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]);
+			StringInfoData intersectbuf;
+			StringInfoData replacementsbuf;
+			char	   *pk_only = pk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+				"" : "ONLY ";
+
+			quoteOneName(attname, RIAttName(fk_rel, riinfo->fk_attnums[riinfo->nkeys - 1]));
+			sprintf(paramname, "$%d", riinfo->nkeys);
+
+			appendStringInfoString(&querybuf, " AND NOT coalesce(");
+
+			/* Intersect the fk with the old pk range */
+			initStringInfo(&intersectbuf);
+			appendStringInfoString(&intersectbuf, "(");
+			ri_GenerateQual(&intersectbuf, "",
+							attname, fk_period_type,
+							riinfo->period_intersect_oper,
+							paramname, pk_period_type);
+			appendStringInfoString(&intersectbuf, ")");
+
+			/* Find the remaining history */
+			initStringInfo(&replacementsbuf);
+			appendStringInfoString(&replacementsbuf, "(SELECT pg_catalog.range_agg(r) FROM ");
+
+			quoteOneName(periodattname, RIAttName(pk_rel, riinfo->pk_attnums[riinfo->nkeys - 1]));
+			quoteRelationName(pkrelname, pk_rel);
+			appendStringInfo(&replacementsbuf, "(SELECT y.%s r FROM %s%s y",
+							 periodattname, pk_only, pkrelname);
+
+			/* Restrict pk rows to what matches */
+			querysep = "WHERE";
+			for (int i = 0; i < riinfo->nkeys; i++)
+			{
+				Oid			pk_type = RIAttType(pk_rel, riinfo->pk_attnums[i]);
+
+				quoteOneName(attname,
+							 RIAttName(pk_rel, riinfo->pk_attnums[i]));
+				sprintf(paramname, "$%d", i + 1);
+				ri_GenerateQual(&replacementsbuf, querysep,
+								paramname, pk_type,
+								riinfo->pp_eq_oprs[i],
+								attname, pk_type);
+				querysep = "AND";
+				queryoids[i] = pk_type;
+			}
+			appendStringInfoString(&replacementsbuf, " FOR KEY SHARE OF y) y2)");
+
+			ri_GenerateQual(&querybuf, "",
+							intersectbuf.data, fk_period_type,
+							riinfo->agged_period_contained_by_oper,
+							replacementsbuf.data, ANYMULTIRANGEOID);
+			/* end of coalesce: */
+			appendStringInfoString(&querybuf, ", false)");
+		}
+
 		appendStringInfoString(&querybuf, " FOR KEY SHARE OF x");
 
 		/* Prepare and save the plan */
@@ -2251,7 +2340,8 @@ ri_LoadConstraintInfo(Oid constraintOid)
 
 		FindFKPeriodOpers(opclass,
 						  &riinfo->period_contained_by_oper,
-						  &riinfo->agged_period_contained_by_oper);
+						  &riinfo->agged_period_contained_by_oper,
+						  &riinfo->period_intersect_oper);
 	}
 
 	ReleaseSysCache(tup);